I remember many years ago when I was in basic training, I was awaked around 2am by a scuffle going on at another bunk across from me (we shared 8 men rooms, then). Four guys were subduing and carrying away one of the trainees, one guy per limb. Never saw the guy again. He had a reputation as being somewhat "crazy". He told me once that the reason he joined the army was to learn how to kill so that he could then be an assassin for the mob. He used to stroke his weapon (M-14, then) and talk to it.

I doubt that any criminal organization would actually hire this guy, but my point is that sometimes it does not take conflicting religions or philosophies to make someone do something like Sandy Hook, just someone who is "crazy", which I am defining as someone who would do something like this.

As others have mentioned, you cannot legislate against crazy. Perhaps invest, as a society, in better mental health practices, would help........but, there will always be that outlier that we can't control or predict, then what?

So, a gun in every classroom? As a teacher friend of mine once said, and I paraphrase: "Believe it or not, teachers did not go into the teaching profession to carry weapons". Individually we can take some measure of control and do something, even if it it just an extra dollop of awareness. As a society, what? There does not seem any likelihood of a consensus here. Still, is there any practical measures that can be taken?